YOURLS is a free URL shortener service you can run on your webhost to have your own personal TinyURL.
This plugin is a bridge between YOURLS, Twitter and your blog: when you'll submit a new post or page, your blog will tap into YOURLS to generate a short URL for it, and will then tweet it.
Note that, for maximum fun, this plugin also supports a few other public URL shortener services: tr.im, is.gd, tinyURL and bit.ly




